The subject application is related to subject matter disclosed in the Japanese Patent Application No.Hei11-263702 filed in Sep. 17, 1999 in Japan, to which the subject application claims priority under the Paris Convention and which is incorporated by reference-herein.
1. Field of the Invention
The present invention relates to a high-frequency package for encapsulating a circuit device having a microwave circuit or the like, and the manufacturing method thereof.
2. Description of the Related Art
A microwave circuit for amplifying a high-frequency signal of microwave or the like comprises commonly semiconductor devices such as field-effect transistors and circuit devices including capacitors and resistors. The semiconductor devices and the circuit devices are air-tightly encapsulated in a high-frequency package.
Such a high-frequency package comprises a ceramic frame having an inner space for accommodating the semiconductor devices and the circuit devices and such as a base plate on which the ceramic frame is placed. A pattern of circuits for transmitting signals are provided on the ceramic frame.
A method for manufacturing such a high-frequency package includes applying a dose of paste, for example, tungsten paste, onto the ceramic frame made of a ceramic material such as alumina and baking the paste together with the ceramic frame to form the patterned circuits. This is followed by bonding the ceramic frame to the base plate and leads to the circuit pattern on the ceramic frame by means of silver brazing.
In the method of manufacturing a convention high-frequency package, the pattern of circuits are baked and then the bonding between the ceramic frames and the base plate and between the patterned circuits and the leads is carried out by brazing. The method hence has the following technical disadvantages.
A conventional method for manufacturing a high-frequency package includes a baking step and two joining steps for developing circuit patterns and its overall procedure will hardly be facilitated.
Also, the joining is implemented by a brazing technique which requires particular jigs for supporting work pieces to be joined and its apparatus will be intricate.
It is an object of the present invention to provide a high-frequency package which can eliminate the above technical disadvantages and be fabricated by a simpler procedure.
It is another object of the present invention to provide the high-frequency package manufacturing method which can make the manufacturing process more simple and ease.
The high-frequency package according to the present invention comprises a base plate made of copper; a ceramic frame having a space for accommodating a circuit device and mounted on the base plate; and a pattern of circuits developed on the ceramic frame, wherein the base plate and the ceramic frame, the ceramic frame and the patterned circuits are both joined together by a DBC technique.
According to this package, the high-frequency package can thus be fabricated by a simpler procedure.
The high-frequency package manufacturing method according to the present invention comprises the steps of: the first step of mounting a ceramic frame, having a space for accommodating a circuit device, on the base plate made of copper; the second step of arranging the lead members for circuit pattern on the ceramic frame; the third step of bonding the base plate to the ceramic frame and the ceramic frame to the lead members at one time by a DBC technique.
According to this method, it is possible to make the high-frequency package manufacturing process simple and ease.